Tsunami Hazard level: Very low ?

Tsunamis are large ocean waves generated by sudden displacement of water, most commonly caused by undersea earthquakes, but also by submarine landslides and volcanic eruptions. These waves can travel across ocean basins at high speeds and grow to destructive heights as they approach shallow coastal waters. The severity of tsunami hazard depends on the magnitude of the triggering event, ocean bathymetry, coastal topography, and the presence of natural or built protective features.

In the area you have selected (Administrative unit not available) tsunami hazard is classified as very low according to the information that is currently available. This means that there is less than 0.04% chance per year of a potentially-damaging tsunami occurring (less than 2% chance in the next 50 years). Based on this information, the impact of tsunami does not need to be considered in different phases of the project. Further detailed information should be obtained to adequately account for the level of hazard. Although the hazard is considered to be very low or non-existent in the project location based on the information available in ThinkHazard!, additional information may show some level of hazard. If local or additional information sources suggest that there is tsunami hazard, seek expert guidance on additional recommended actions.

Climate change impact: The areas at risk of tsunami will increase as global mean sea level rises. According to the IPCC (2013), global mean sea level rise depends on a variety of factors, and estimates for 2100 range from ~20 cm to nearly 1 m. However, regional changes in sea level are difficult to predict. Projects in low-lying coastal areas such as deltas, or in island states should be designed to be robust to projected increases in global sea level.

Recommendations

• REGULATIONS: Check with local authorities to identify any local regulations concerning tsunami hazard and impacts. Ensure that the project conforms to existing tsunami avoidance zone land use planning regulations, flood regulations and any existing plans for warning and evacuation. More information
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  CONTEXT:

  • Around the world there is increasing recognition that avoiding development in the most frequently tsunami (or river flood or storm surge) inundated areas is one of the most effective means of managing future losses to natural hazards. Therefore, the planning for new developments should include consideration of already-existing national or regional regulations and guidelines
  • Many countries have some form of formal legislation, regulation or guidance for tsunami risk mitigation. These may broadly cover such aspects as:
  • Land-use planning, controlling the location of development for all or some types of building or project
  • Warning, through natural signs (earthquake, ocean disturbance), local initiatives and/or Tsunami Warning Centres
  • Response planning, usually focussed on life safety, evacuation routes, signage and safe locations
  • Public alerting mechanisms such as mobile phone apps, sirens, radio etc.
  • Hard defence options
  • Vertical evacuation options
  • Risk assessment

  MITIGATION:

  • Note that avoidance of a natural hazard such as tsunami is the most effective form of risk mitigation, but this should be a decision made based on the informed understanding of social, economic and political risk.
  • Comply with laws and regulations including land-use planning and flood management. Design the project to best integrate the regulations.
  • Comply with all Health and Safety obligations appropriate to the hazard level.
  • If the location of the project conflicts with land-use planning regulations, or cannot comply with warning and evacuation regulations consider relocation of the project.

  Links:

  International Tsunami Information Centre http://itic.ioc-unesco.org/index.php

  Pacific Tsunami Warning Centre: http://ptwc.weather.gov/

  Indian Ocean Tsunami Warning and Mitigation System (ICG/IOTWMS), more information at: http://www.ioc-tsunami.org/index.php?option=com_content&view=article&id=8&Itemid=58&lang=en

  North-Eastern Atlantic, Mediterranean and connected seas: Tsunami Information Centre. http://neamtic.ioc-unesco.org/

  Examples:

  NZ tsunami warning plan – http://www.civildefence.govt.nz/cdem-sector/cdem-framework/guidelines/national-tsunami-advisory-and-warning-plan/

  NZ tsunami evacuation mapping guideline – < http://www.civildefence.govt.nz/assets/Uploads/publications/dgl-08-08-tsunami-evacuation-zones.pdf>

  NZ public notification options assessments - http://www.civildefence.govt.nz/cdem-sector/cdem-framework/guidelines/public-alerting-options-assessment/

  Integrating tsunami inundation modelling into land use planning http://www.eqc.govt.nz/sites/public_files/1604-tsunami-inundation-modelling-into-land-use-planning_0.pdf

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• SEEK INFORMATION: Investigate the tsunami risk in the area in more detail (see additional information). Consider whether local site conditions (nearshore bathymetry and topography) could amplify tsunami hazard.